Facebook CEO Mark Zuckerberg started sharing some rare photos of its data center in the forests of Northern Sweden, where Facebook is taking advantage of the low temperature and nearby rivers to increase efficiency and save power. The massive Luleå data center, which is the size of six football fields, uses enormous fans to “pull in the outside air to naturally cool the thousands of warm servers that line the center’s broad hallways,” writes Zuckerberg in a post on his Facebook page. He adds:

“You probably don’t think about Luleå when you share with friends on Facebook, but it’s an example of the incredibly complex technology infrastructure that keeps the world connected. I’m looking forward to sharing photos of more of our advanced technology soon.”

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